How much is a good amount to pump

I fed baby, 2 weeks old, then pumped about 30-45 minutes after for about 20 minutes, two let downs each side. I only got an ounce 😔 I only pumped to see how much I’m producing, and to increase my supply. He’s been cluster feeding for a few days now which is probably a growth spurt, but I feel really defeated right now. I know he needs more than an ounce per feeding. Help 😔